The National Security Agency monitored the phone conversations of 35 world leaders after being given the numbers by an official in another US government department, according to a classified document provided by whistleblower Edward Snowden.

The confidential memo reveals that the NSA encourages senior officials in its "customer" departments, such as the White House, State and the Pentagon, to share their "Rolodexes" so the agency can add the phone numbers of leading foreign politicians to their surveillance systems.

The document notes that one unnamed US official handed over 200 numbers, including those of the 35 world leaders, none of whom is named. These were immediately "tasked" for monitoring by the NSA.

The NSA memo obtained by the Guardian suggests that such surveillance was not isolated, as the agency routinely monitors the phone numbers of world leaders – and even asks for the assistance of other US officials to do so.

The memo, dated October 2006 and which was issued to staff in the agency's Signals Intelligence Directorate (SID), was titled "Customers Can Help SID Obtain Targetable Phone Numbers".

The NSA memo seen by the Guardian was written halfway through George W Bush's second term, when Condoleezza Rice was secretary of state and Donald Rumsfeld was in his final months as defence secretary.

Angela Merkel, the German chancellor, said she and her French counterpart would launch a “joint initiative” to renegotiate their intelligence services’ co-operation with the US, saying protocols must be set following revelations of widespread American eavesdropping on European leaders.

“I think the services need to come to agreement between each other on yardsticks and other norms and standards,” Ms Merkel said at a press conference after the first day of a two-day summit in Brussels. “Words are not sufficient. True change is necessary.”

The insistence on renegotiating the agreements is likely to ratchet up the transatlantic tensions over spying by the US National Security Agency, which Berlin alleges tapped into Ms Merkel’s personal mobile phone.

Over the course of the past week, several media organisations relying on documents supplied by former NSA contractor Edward Snowden have reported extensive spying operations in France, Germany and Italy.

The German chancellor said she has not changed her communications behaviour, adding it was unclear whether her encrypted mobile used for government work or a non-secure line she uses for party politics was being tapped.

“This partnership . . . is a partnership that has stood the test of time,” Ms Merkel said of US-German ties. “But for the future, things have to change and they have to change radically.”

Whistleblower Snowden Explains Himself

Edward Snowden - US, World Hero

Edward Snowden, the man who leaked NSA data to the Guardian is a wanted man in the US. I consider him a national hero. Ironically, many countries who benefited from his leaks, including France and Germany, refuse to grant Snowden political asylum.

Last summer, France and Portugal would not grant air space to the plane carrying Bolivian president Evo Morales, based on false US intelligence that Snowden was aboard. Morales' plane was forced to make an unscheduled stopover in Vienna.

The Snowden affair is an absolute disgrace all around: By the US for its actions, then by Spain, by Portugal, by France and by any country that would not grant air clearance to Bolivia President Evo Morales based on totally unfounded and piss poor US intelligence reporting that suggested Snowden was on Morales' plane.

Even if countries were 100% certain Snowden was on the plane, they should not have honored the request by the US to ground the plane or deny air space flyover.

I am disappointed that neither New Zealand nor Australia would offer asylum.

Is there any dignity left in this world?

I guess not, given the world bows down to the almighty US even when we spit in the face of our key allies by bugging their offices.